Hypodekmxc syringe



Jan. 10, 1928. 1.65.5,909

A. A. LAURENT HYPODERMIC SYRINGE Filed Feb. 17, 1927 In venfor:

(K Laurent W 4 B9 /(ZTornays Patented Jan. 1d, 1.9325.

.UNITD STATES ANTOINE A. LAURENT, OF MINNEAPOLIEl, MINNESOTA.

HYPODERMIG SYRINGE.

Application filed February 17, 1927. Serial No. 168,932.

My invention relates to hypodermic syringes,-and has for an object to provide a syringe which can be held and operated with great convenience, and which can be 1naintained filled with a supply of liquid to be injected hypodermically into the human body. The syringe is employed to inject liquid into the human body for the production of whatis known as local anaesthesia, and may also be used for injecting seruins and vaccines. It is essential for producing local anwsthesia to introduce relatively large quantities of the liquid into the area to be anaesthetised and it is, therefore, desirable that the syringe be so constructed that it can be refilled or kept in a tilled condition with out having to remove the hypodermic needle after the latter has been inserted. This in, vention is in the nature of an improvement on Patent No. 1,367,008 granted Feb. 1, 1921, to A. N. Bessesen and involves an improve ment in connection with the valve construction and arrangement disclosed in said patent.

The full objects and advantages of my invention will appear in connection with the detailed description thereof, and the novel features of my inventive idea will be particularly pointed out in the claims.

In the accompanying drawings which illustrate a practical embodiment of my in vention,

Fig. 1 is a view of the device partly in elevation and partly in central vertical section and showing the plunger moved inwardly. Fig. 2 is a view of the device in central vertical section showing the plunger moved outwardly. Fig. 3 is a view in section on the line 33 of Fig. 2.

Referring to the drawings for the purpose of describing the invention in detail, the syringe includes a cylindrical barrel 10 which at its forward end is threaded to receive a perforated cap 12. This cap is in turn threaded on its forward end to receive a hypodermic needle 14:. The interior of the lower portion of the barrel 10 is provided with a valve seat 16 with which a forwardly opening check valve 18 is adapted to cooperate, the latter being normally held on the valve seat by a spring 20. The valve 18 is in the form of a ball to which is secured a stem 22 extending out through the passage in the cap 12 but smaller than this passage so not to prevent the flow of liquid therethrough. The rear and of the curved finger grips 26.

barrel 10 is provided with a screw cap 2d having two lateral diametrically opposite @lidable in the barrel 10, there is a plunger 28 having a vertical. screwthreaded opening into which the lower end of a hollow rod 30 is threaded. The longitudinal passageway 32 in this rod is closed at the bottom by a ho t 3 1- having a head 36 at one end and whose other end has a screwthreadcd portion 38 which is screwed into the passage 32. The portion of the bolt between its head and screwthreaded portion extends loosely through a central opening in a plunger valve 10. The head 36 of the bolt is elongated as shown in Fig. 3 and fits into a circular recess in the bottom of the valve lO so that the passage through the valve around the bolt is not obstructed. Inclined perforations 42 lead through the rod 30 and the plunger 28 beginning above the upper end of the bolt and passing through the lower surface of the plunger 28 about midway between its center and periphery. The contiguous surfaces of the plunger and plunger valve lit each other snugly when engaged so as to close the lower ends of the perforations d2 at such time. The hollow rod l6 passes snugly through a central opening in the cap 24- and at its upper end is threaded to receive an internally threaded boss 4A- formed on a hand piece 4-6 shaped to receive the palm of the hand. The hand piece 46 contains a passageway 1-8 which communicates withthe passageway 32 and also extends through a nipple 50 to which is attached a piece of rubber tubing 52 adapted to be connected with the source of liquid supply. The upper end of the plunger 28 has a sleeve portion 5 L containing internal threads which receive the lower coils of a spring 56 whose upper end is anchored to a ring 56 held between the cap 24: and the upper end of the barrel 10.

In use, the hypodermic needle may be readily inserted wherever desired in the human body and with the fingers of the operator around the finger grips 26 and the palm of his hand upon the handpiece i6, pressure is exerted upon the plunger to cause the liquid below the latter to be forced through the needle into the part to be anzesthetized or into the part into which serum or vaccine is to be injected. At the same time, the spring 56 is stretched and. the plunger valve 10 moves into engagement Ill) with the lower surface of the plunger 28 ing its upper end screwed into the lower thereby closing the passage through the perlorations li Upon releasing the pressure of the hand, the spring retracts the plunger thereby producing a vacuum. in the barrel below the plunger and causing liquid to flow from the source of supply into the vacuum chamber, the plunger valve then as suming the position shown in Fig, 2 so that there is a tree passage for liquidthrough the perforations 42 andpastthe bolt Se. Upon starting-to depress the plunger, the valve '10 immediately moves-into position in engagementwith the lower end of the plunger as 7 shown in Fig, 1 so that back low of liquid is'preventedf is a special utility i'or thestein 22 tachel to the check valve 18 due-to, the fact that tliere is liability of this valve becoming stuck to its seat fter the dc vicehas been in use. When such sticking occurs, the valve isreadily released by pushing; side'wise on the projecting end of the stem when the needle is detached. T he cXtent of movement or the plunger valve relati' ely to theliilunger may be varied by turning the screw bolt upwardly or downwardly as desired to efl'ect the proper adjustment.

I claim:

1. Ina hypoderinicsyringe having a barrel provided with an outlet opening containingan outwardly opening check valve, the combination of a plunger working in said bfarreha hollow rod attached at its inner end to said plunger, a plunger valve secured for limitedinovement with relation to the inner -lll containing r inclined perforations passing through said rod and opening through said inner surface, and means for connecting the outer end ol 'said rod with a source of liquid supply. r V

2. ln a hypodermic syringe having a barrel provided with an outlet opening containing an outwardly opening check valve, the combination of a plunger working in said barrel, a hollow rod attached at its lower end to said plunger, a screw bolt havend oi? said rod, a plunger valve mounted on the lower portion of said bolt for limited movement thereon, said rod and plunger containing inclined perforations passing through said rod and opening through the lower surface of said plunger, and means for connecting the outer end of said rod with a source of liquid supply.

3. in a hypodern'iic '1i.l1;1c having a barrel provided with an outlet opening our taining an outwardl opening chcclr valve, the combination oi a plunger worlrii'lg in said valve, a hollow rod attached at its lower end. to said plunger, a screw bolt having its upper end screwed into the lower end of said rod, :11 plunger valve containing an opening 01' larger size the said bolt, the latter pus: up, through said opening wherclry said plungn r valve has a limited movement with relation to the lower surface oil said plui said rod and plunger containinginclined pcrforations passing through said rod and opening through the lower surl'acc oi" said plunger, and means for connecting the outer end of said rod with a source of liquid. supply.

d. In a hypodermic syringe having a barrel proyided with an outlet opening; con taining an outwardly opening check valve, the combination of plunger working in said barrel, a hollow rol attached at its inner end to said plunger, :1 projecting stein secured to the lower end of said rod, plunger valve having an opening therethrough of lar er diameter than said atom for receiving tne latter and permitting said valve to have a limited niovcnicnt thereon, said rod and plunger coi'itaininp inclined perforations passing through said rot and opening through the inner surface of said plungeigvand means for connecting the outer end of said rod with a emu-cc ol liquid supply.

In testimony whereol I hereunto allix my signature. 

